Sealing rolls with yieldable shoes

ABSTRACT

Apparatus for sealing the ends of covering sheets for absorbent pads or fillers includes a bed roller with spaced lands and an anvil roller with a plurality of individual anvil shoes or segments which coact with the lands on the roller to emboss links between pads. The anvil shoes are individually adjustably and yieldably mounted in a slot in the anvil roller to compensate for the varying thickness of intervening material and for misalignment or thermal distortion of the heated lands on the bed roller which can cause imperfect heat sealed seams. Biasing springs and adjustment screws for each anvil shoe enable minute independent adjustments of each of the anvil shoes and permit the shoes to yield during use, thus to provide uniform, neat heat sealed bands or embossed strips which secure the fillers within the covering sheets.

Johnson Nov. 27, 1973 SEALING ROLLS WITH YIELDABLE SHOES [52] US. Cl156/582, 29/121 A, 101/6,

425/363 Int. Cl B321) 31/00, B21b 27/02 Field of Search 156/580, 582,220;

[56] References Cited UNITED STATES PATENTS 6/1920 Simpson 101/6 9/1960-Huck 29/121 R 8/1948 Rosenlof 101/6 Primary Examiner-Douglas J. DrummondAttorney-Wheeler, House & Wheeler [57] ABSTRACT Apparatus for sealingthe ends of covering sheets for absorbent pads or fillers includes a bedroller withspaced lands and an anvil roller with a plurality ofindividual anvil shoes or segments which coact with the lands on theroller to emboss links between pads. The anvil shoes are individuallyadjustably and yieldably mounted in a slot in the anvil roller tocompensate for the varying thickness of intervening material and formisalignment or thermal distortion of the heated lands on the bed rollerwhich can cause imperfect heat sealed seams. Biasing springs andadjustment screws for each anvil shoe enable minute independentadjustments of each of the anvil shoes and permit the shoes to yieldduring use, thus to provide uniform, neat heat sealed bands or embossedstrips which secure the fillers within the covering sheets.

11 Claims, 7 Drawing Figures PAIENIEUunv 2 1 :975

SHEET 10F 2 SEALING ROLLS WITH YIELDABLE SHOES BACKGROUND OF INVENTIONPrior art apparatus for heat sealing pad or filler covering sheets toenclose the tiller includes a bed roller with heated land segments whichcoact with corresponding lands on an anvil roller. Continuous webs ofupper and lower covering sheets with spaced fillers located between thewebs are delivered through the gap between the anvil roller and bedroller. The heated lands on the bed roller form heat seal bonds on thecovering sheets as the bed roller segments and anvil segments cometogether. The lands separate asthe body of the filler moves between therollers and again meet to form a heat sealed seam across the succeedingfiller gap. Subsequently the pads are separated by a cut-off knife whichprovides a medial cut in the gaps between the fillers.

Inasmuch as the covering sheets for the fillers are relatively thin, thegaps between the lands on the bed roller and the anvil roller must bewithin close tolerances to apply uniform and complete heat seal bands.The

embossed seals typically overlap thicker pad zones. Slight misalignmentbetween the anvil lands and bed roller lands results in imperfect andnonuniform heat seal seams. Even though the bed roller lands and anvillands are true and in proper alignment when the bed roll is not heated,thermal and other distortion during use can cause misalignment.

SUMMARY OF INVENTION The invention overcomes the alignment problemscaused by thermal and other distortion of the bed roller lands byproviding an anvil roller with a plurality of independently adjustableand yieldable arcuate anvil segments or shoes each of which coacts withan opposed ridge or land segment on the heated bed roll.

The anvil shoes have out-turned tabs which are received in alongitudinal or axial slot in the anvil roller. Intumed retainingflanges on the anvil roller form the top of the slot and are spaced fromthe base of the slot to provide clearance for the anvil tabs to providean adjustr'nent and yield range for the anvil shoes. The anvil shoes arearranged in side by side relationship in the slot and have accuratelymachined abutting side surfaces. Recesses in the side surfaces minimizeadhesion between anvil shoe surfaces, thus enabling minute independentadjustments of the position of the segments to compensate for distortioncaused by heating of the bed roller. A removable end block on the anvilroller facilitates assembly of the anvil shoes in the slot and securesthe anvil shoes in place.

Each anvil shoe desirably has two adjustment screws. The adjustmentscrews are threadably received inapertures extending through the anvilroller. Counterbores opening into the anvil roller slot carry springswhich engage the base of the anvil shoes and yieldably urge the anviltabs against the inturned slot flanges.

Further objects, features, and advantages of the present invention willbecome apparent from the following disclosure.

DRAWINGS FIG. 1 is a fragmentary end view of heat seal apparatusemploying a heated bed roller and embodying the anvil roller of theinvention. 1

FIG. 2 is a fragmentary side view of the apparatus shown in FIG. 1.

FIG. 3 is an enlarged sectional view along line 33 of FIG. 1, aworkpiece being shown in course of passage through the gap between thebed roll and anvil roll.

DESCRIPTION ,OF PREFERRED EMBODIMENT Although the disclosure hereof isdetailed and exact to enable those skilled in the art to practice theinven-. tion, the physical embodiments herein disclosed merely exemplifythe invention which may be embodied in other specific structure. Thescope of the invention is defined in the claims appended hereto.

The heat sealing apparatus 10 (FIG. 1) includes a bed roller bar 12rotatably supported in a frame 13 and having a heated face bar 11 formedwith a plurality of spaced arcuate lands or ridges 14 (FIGS. 3, 4) whichextend axially along the periphery of the roller 12. The lands 14 have arelatively short arcuate extent (approximately 80 in the disclosedembodiment) and are concentric with the axis of roller 12. The face bar11 of bed roller 12 contains two thermal heating bars or units 17 (FIG.4) located in axial bores 19 (FIG. 3) for heating the lands l4.Collector assemblies 16 (FIG. 1) at each end of the bed roller 12connect the heating units 17 to a source of electric current.

Cooperating with bed roll 12 is an anvil roller 22 (FIGS. 1, 3, 4, 5)which is supported in frame 13 by bearings 25 for rotation in adjacentrelation to the bed roller 12. The anvil roller 22 is provided with aplurality of separately independently adjustable and yieldable anvilsegments or shoes 24, each having an arcuate peripheral surface 26 withan arcuate extent or angular span substantially the same as the bedroller lands 14.

The anvil shoes 24 are radially aligned with the lands 14 of the bedroller 12 (FIG. 4).

Chains engaged with sprockets 21, 22 (FIG. 2) on the bed roller 12 andanvil roller 22, rotate the bed roller lands 14 in phase with the anvilshoes 24 for intermittent co-action in synchronization with movement ofthe intervening spaced pads and covering sheets as subsequentlydescribed.

Means are provided for adjustably mounting each of the anvil shoes 24 inthe anvilroller 22. In the disclosed construction the means includes alongitudinal or axial slot 30 (FIG. 3) in the anvil roller 22 which isopen at one end for assemblying the anvil shoes 24 endwise into the slot30 in a serial array. Each anvil shoe 24 has a base 33 with projectingtabs 32. The tabs 32 are located between the base 29 of the slot 30 andoverhanging retaining flanges 31 (FIG. 3) on the anvil roller 22.Sufficient clearance is provided between the flanges 31 and the base 33of the slot 30 to permit radial adjustment and yielding movement of theanvil shoes as presently described. The ends 37 of the flanges 31 arespaced to embrace the end walls 47 of the anvil shoes.

The means for adjustably and yieldably mounting the anvil shoes 24 alsoincludes two springs 34, 35 (FIGS. 3, for each shoe 24. The springs 34,35 are located in counterbores 36 of apertures or bores 27 which extendthrough the anvil roller 22. The counter-bores 36 open into slot 30 toallow the springs 34, 35 to press against the base 33 of the anvil shoe.

Adjustment screws 38, 39 threadably received in the apertures 37 enableadjustment of the tension of the springs 34, 35 and thus the positionand degree of yieldability of the anvil shoe 24 in the slot 30. Lockingscrews 41 can also be employed to fix the adjustment. The adjustmentaforesaid permits radial inward and outward movement of the shoe asrequired to compensate for distortion or misalignment of the opposed bedroller land 14, whether thermally induced or otherwise.

The anvil shoes 24 have accurately machined abutting side surfaces 42which are provided with a plurality of concave recesses 44 (FIGS. 3, 6)thus to reduce adhesion between abutting surfaces so that minute andindependent adjustments of the relative positions of the anvil shoes 22can be made.

The springs 34, 35 for adjacent anvil shoes 24 are desirably staggered(FIGS. 5 and 6) to enable use of large diameter springs with the desiredspring rate. The base 33 of each anvil shoe has appropriately locatedsemicircular recesses 43 (FIG. 6) opening into the side surfaces 42 toreceive overlapping edge portions of the springs for the adjacent anvilshoe and prevent imposition of spring pressure from the springs for oneshoe on the undersurface of the adjacent shoe. The recesses on adjacentshoes also function as pilots to maintain the springs in centeredpositions.

In use of the apparatus upper and lower covering sheets or opposed plies50, 52 of thermo-sealable webbing embracing spaced fillers in the formof bats, pads or wadding material 54 located between the plies 50, 52(FIG. 3) are fed between the bed roller 12 and anvil roller 22. Thelands l4 and anvil shoes .24 come together in synchronization withmovement of the covering sheets 50, 52 and the gaps 53 between the bats54, thus to apply a series of spaced heat seal unions 57 across the webto links 55 between adjacent fillers 54, thus to form a chain of fillers54 interconnected by the heat sealed links or seams 55 on the coveringsheets 50, 52. The unions 57 also overlap the ends 59 of the tiller 54and heat seal the covering sheets 50, 52 to the filler to anchor thefiller 54.

Subsequently discrete pads 58 are separated from the chain by transversecuts 61 midway through the seam 55 (FIG. 7).

The adjustment capability of the anvil shoes 24 enables independentadjustment and yielding of each anvil shoe 24 to adjust the pressure ofthe shoes against varying thicknesses of the intervening material. Thisis illustrated in FIG. 7 which shows how the embossed pattern of theseals 57 typically extend throughout the link zone 55 and substantiallyoverlaps the zone of the batts 54. The link zone 55 is very thin, as itconsists only in the double ply thickness of the cover sheets 50, 52,each of which is only about 0.001 inches thick. The zone of the batt S4is much thicker. Accordingly, the anvils 24 must react in eachimpression to thick and thin intervening material. The independentyielding mounting of each anvil permits it to follow the specificthickness of the intervening material while maintaining at all times arelatively uniform pressure which will not tear the relatively thincover sheets in link zone 55, nor dig holes through or rupture thesheets in the zone of batts 54. The thicker zone of batts 54 has acushion effect on the anvils 24, thus further militating against damageto the thin link zone 55.

The disclosed structure enables the anvils to react quickly to varyingthickness intervening material even at high speed machine operations andnot withstanding thermal and other dislocations in the coacting parts.

I claim:

1. Apparatus for uniting opposed plies of scalable material, saidapparatus comprising a bed roller having a series of axially spacedlands, an anvil roller, a corresponding series of anvil shoes coactingwith said bed roll lands to apply a seal band interconnecting theopposed plies and means for individually yieldably mounting said shoesin said anvil roller to vary the positions of said shoes relative tosaid lands, said means including means for individually adjusting theyieldability of said shoes and comprising apertures in said anvil rollercommunicating with said shoes, springs in said apertures engaging saidshoes and screws threadably received in said aperture and engaging saidsprings to vary the tension on said springs and the position of saidshoes in said roller.

2. The apparatus of claim 1 in which one of said series of lands andshoes is heated.

3. Apparatus in accordance with claim 1 wherein said means comprises anaxially extending slot in said anvil roller, said anvil shoes havingbases slidable along said slot.

4. Apparatus in accordance with claim 1 wherein said slot has a base,and said means includes intumed retaining flanges on said anvil rollerpartially spanning and defining the top of said slot and spaced fromsaid slot base to freely receive tabs on said anvil shoes.

5. Apparatus in accordance with claim 1 wherein said anvil shoes are inlateral contact, said anvil shoes having machined contacting sidesurfaces.

6. Apparatus in accordance with claim 5 wherein said side surfaces haverecesses to minimize adhesion.

7. In apparatus for applying seal seams to the links between seriallyconnected pads, said apparatus incl uding a bed roller with a pluralityof axially spaced lands and an opposed anvil roller, the improvementcomprising a serial array of anvil shoes and means for mounting saidshoes in said anvil roller to afford independent movement of each ofsaid shoes with respect to its opposed land, said means comprising anaxial slot in said roller, said slot being defined by a slot base andinturned flanges spaced from said base and out-tumed tabs on each ofanvil shoes received in said slot, said means also including twoadjustment screws for each of said anvil shoes, and apertures in saidanvil roller, said apertures opening into said slot and threadablyreceiving said adjustment screws.

8. The improvement of claim 7 including springs located in saidapertures between said shoes and said screws.

9. The improvement of claim 8 wherein said springs are staggered andoverlap adjacent shoes, and recesses in said adjacent shoes to receivesaid springs.

10. The improvement of claim 7 in which said means further comprisessprings against which said anvil shoes are independently yieldable.

11. The improvement of claim 12 in combination with means for heatingone of the lands and shoes.

* i w nm

1. Apparatus for uniting opposed plies of sealable material, saidapparatus comprising a bed roller having a series of axially spacedlands, an anvil roller, a corresponding series of anvil shoes cOactingwith said bed roll lands to apply a seal band interconnecting theopposed plies and means for individually yieldably mounting said shoesin said anvil roller to vary the positions of said shoes relative tosaid lands, said means including means for individually adjusting theyieldability of said shoes and comprising apertures in said anvil rollercommunicating with said shoes, springs in said apertures engaging saidshoes and screws threadably received in said aperture and engaging saidsprings to vary the tension on said springs and the position of saidshoes in said roller.
 2. The apparatus of claim 1 in which one of saidseries of lands and shoes is heated.
 3. Apparatus in accordance withclaim 1 wherein said means comprises an axially extending slot in saidanvil roller, said anvil shoes having bases slidable along said slot. 4.Apparatus in accordance with claim 1 wherein said slot has a base, andsaid means includes inturned retaining flanges on said anvil rollerpartially spanning and defining the top of said slot and spaced fromsaid slot base to freely receive tabs on said anvil shoes.
 5. Apparatusin accordance with claim 1 wherein said anvil shoes are in lateralcontact, said anvil shoes having machined contacting side surfaces. 6.Apparatus in accordance with claim 5 wherein said side surfaces haverecesses to minimize adhesion.
 7. In apparatus for applying seal seamsto the links between serially connected pads, said apparatus including abed roller with a plurality of axially spaced lands and an opposed anvilroller, the improvement comprising a serial array of anvil shoes andmeans for mounting said shoes in said anvil roller to afford independentmovement of each of said shoes with respect to its opposed land, saidmeans comprising an axial slot in said roller, said slot being definedby a slot base and inturned flanges spaced from said base and out-turnedtabs on each of anvil shoes received in said slot, said means alsoincluding two adjustment screws for each of said anvil shoes, andapertures in said anvil roller, said apertures opening into said slotand threadably receiving said adjustment screws.
 8. The improvement ofclaim 7 including springs located in said apertures between said shoesand said screws.
 9. The improvement of claim 8 wherein said springs arestaggered and overlap adjacent shoes, and recesses in said adjacentshoes to receive said springs.
 10. The improvement of claim 7 in whichsaid means further comprises springs against which said anvil shoes areindependently yieldable.
 11. The improvement of claim 12 in combinationwith means for heating one of the lands and shoes.